星星草对碱化土壤物理性质的影响

研究不同生长年限的星星草对碱化土壤及对应碱斑土壤的机械组成、土壤孔隙度、容重和含水量的影响。结果表明,星星草生长1、2和3年后,粘粒和细砂所占比例减小,而粗粉和细粉所占比例增大。土壤总孔隙度、毛管孔隙度和非毛管孔隙度随着生长年数的增加呈不同程度的增加,而土壤容重则越来越小,>0.25mm的水稳定性团聚体随之增加。星星草地土壤含水量和田间持水量均高于碱斑土壤。星星草改善了碱化土壤结构、通透性、保水性和土壤物理环境。     

不同饲用燕麦品种生产性能的综合评价

基于熵权赋权法,运用灰色系统理论中的灰色关联度法对26个燕麦品种的生产性能进行综合评价,结果表明,生产性能综合表现较好的是初岛燕麦、青永久409、青永久709及青永久316;青永久18综合评价值最低,生产性能最差,其余品种生产性能表现一般。经逐步回归分析,发现其中的绿叶数、叶长、茎叶比、鲜干比、生长速度、叶面积指数、相对生长速率及生长天数8个指标对饲用燕麦生产性能贡献显著。     

黄羽肉鸡IGF-1基因单核苷酸多态性与生长性状的相关研究

本试验将类胰岛素生长因子1(IGF-1)作为研究肉鸡生长的候选基因,以海门京海集团的第二世代黄羽肉鸡为试验材料,根据鸡IGF-1基因DNA序列设计引物,采用PCR-SSCP方法进行SNP检测和基因型分析,探讨IGF-1基因多态性与鸡生长性状之间的关系。于IGF-1基因外显子1上发现一处突变。这个突变产生的不同基因型与鸡生长性状进行的统计分析结果表明,个体的1日龄初生重、4周龄、12周龄及300日龄成年体重在不同基因型之间均存在显著差异(P<0.05)。AA基因型1日龄初生重、4周龄、8周龄及300日龄成年体重均显著高于BB基因型个体(P<0.05)。推测可以将IGF-1基因应用于鸡生长的标记辅助选择育种实践。     

Genetic analyses of piglet survival and individual birth weight on first generation data of a selection experiment for piglet survival under outdoor conditions

Genetic parameters of piglet survival traits and birth weight were estimated on the first generation data of a selection experiment aimed at improving piglet survival using a multiple trait linear and threshold model. Data on 5293 piglets for survival at birth, at day one after birth and during the entire nursing period, as well as individual birth weight and litter size, were recorded in an outdoor production system. Genetic effects of piglet survival traits and birth weight were estimated based on threshold and Gaussian models, respectively, using a Bayesian approach. The statistical model included as fixed effects selection group, parity, gender, fostering, gestation length and month of farrowing and, alternatively, an adjustment for litter size. Direct genetic effects (i.e. the piglet's genetic potential) for piglet survival and birth weight were estimated separately, whereas maternal genetic and environmental effects could only be estimated for the given data structure in a combined litter effect. Posterior means of heritabilities for direct genetic effects of survival at birth, at first day after birth and the entire nursing period, as well as birth weight, were 0.08, 0.07, 0.08 and 0.20, respectively. Genetic correlations among survival traits were in the range of 0.29 to 0.40 and indicate that these traits were mainly attributable to different genetic effects. Genetic correlations between direct effects of survival traits and birth weight ranged between 0.18 and 0.23 and were reduced when weights of stillborn piglets were omitted in the analysis or the traits were adjusted for litter size. The magnitudes of direct genetic effects of survival traits are substantially higher than estimates in the literature, which may indicate that these traits have a higher genetic influence under outdoor conditions. The use of birth weight in the multiple trait estimation provided important information for the estimation of survival traits due to its favourable genetic correlations with survival, its high heritability and its high information content as a continuously measured trait.     

Interaction of GH polymorphism with body weight and endocrine functions in Japanese black calves

We assessed the interaction of GH gene polymorphisms (AA, AB and BB genotypes) with body weight and measures of endocrine function in Japanese black calves at 10 months of age. The average body weight for the BB genotype (281+/-5 kg) was significantly lower (P=0.0017, ANOVA) than those for the AA (324+/-9 kg) and AB (317+/-7 kg) genotypes. Plasma concentrations of insulin and IGF-I were greater for the AA genotype than for the AB genotype, and AB and BB genotypes, respectively. There were significant differences in the triglyceride and cholesterol concentrations among the GH genotypes. The area under the basal GH concentration was significantly greater (P=0.0314) for the AA genotype than for the two other genotypes. The incremental area over the basal GH concentrations in response to intravenous GHRH injection (0.4 microg/kg BW) was significantly smaller (P=0.0005) for the BB genotype than for the two other genotypes. In addition, linear regression analysis between GH incremental area induced by GHRH and body weight demonstrated that there was a positive linear correlation (r=0.6496, P<0.002) for incremental areas less than 600 ng min/ml, but a negative correlation (r=0.6473, P<0.05) for incremental areas over 600 ng min/ml. These findings indicate that the GH genotypes of the animals could be associated with difference in the GH response in Japanese black cattle at 10 months of age. We also observed a relationship between genotype and animal performances, but other studies on more animals in different conditions must be realized to make a definite conclusion.     

萨杜湖杂交羊生长性能、羊毛品质及血液生理生化指标测定

为研究萨福克羊×杜泊羊×湖羊杂交羊(萨杜湖杂交羊)生长发育情况及其对当地生态环境的适应能力,采用生产性能常规测定、显微测定和全自动血液生理生化分析仪分别测定了不同年龄阶段萨杜湖杂交羊的体重、体尺指标、羊毛品质(包括不同部位羊毛的净毛率、细度、有髓毛和无髓毛占比、自然长度和伸直长度等指标)和成年羊血液生理生化指标。结果表明:萨杜湖杂交羊早期生长速度较快,初生阶段及周岁时公羊体斜长均显著高于母羊(P<0.05);3月龄时公羊体高、体斜长和胸围均显著高于母羊(P<0.05);6月龄时母羊体重极显著高于公羊(P<0.01),成年时期公羊体重和体高均显著高于母羊(P<0.05);其余各生长阶段内,公母羊间体重及体尺差异不显著(P>0.05)。其成年时平均净毛率较低,为45.21%;长度适中:平均自然长度为4.55cm,伸直长度为6.22cm;细度良好,为17.60μm。公母羊血液生理生化指标及其同国内绵羊参考值相比存在一定的差异,其中母羊血小板总数(PLT)和血小板压积(PCT)均极显著高于公羊(P<0.01),公羊甘油三酯(TG)和白蛋白(ALB)含量显著高于母羊(P<0.05),其余各项指标均无显著差异(P>0.05)。综上所述,萨杜湖杂交羊在生长发育等方面都有不同程度的改进和提高,本试验结果可为该品种杂交羊进一步开发利用提供参考依据。     

影响荷斯坦牛产犊难易的原因分析

通过研究不同胎次、产犊季节和犊牛初生重、犊牛性别、产犊方式等因素对荷斯坦牛难产程度的影响,旨在降低难产率,帮助牛场制定合理有效的繁殖管理措施。试验收集上海金山奶牛场2018年1~12月产犊难易记录共2 812条,采用GLM模型对影响奶牛难产程度的因素进行分析。结果表明,胎次、产犊季节、犊牛初生重、犊牛性别、产犊方式对难产程度有显著影响(P<0.05),且第二胎奶牛自然分娩比例最高;春季和夏季产犊低难产度所占比例较大;随着犊牛初生重的增加,难产程度逐渐增大;生公犊难产程度越大;双胎生产方式难产度增大。     

张掖地区围栏育肥牛场防风墙后不同风速对肉牛场环境及肉牛生产性能的影响

本试验旨在研究防风墙在不同遮蔽距离的减风效果以及风速对牛生产性能的影响。选取初始体重差异不显著的40头牛随机平均分布在选定的4个牛栏中,根据牛栏距防风墙的远近分为2组,测定其日增重。同时根据牛场实际条件和天气状况布置测点,对测点的风速、温度等其他环境指标和肉牛的产热进行现场实测与计算分析。结果表明:安装防风墙的围栏育肥牛场在墙后1.2 m高度,水平遮蔽距离10倍墙高的范围内,可折减风速40%～70%;防风墙后的最佳遮蔽区域是在距离防风墙2～4倍墙高处、水平遮蔽距离6倍墙高距离范围内,风速折减效果明显,最大折减率可达70%左右;肉牛平均体重为480 kg,在外部风冷指数为-15.61的条件下,安装防风墙的围栏育肥牛场的风冷指数可以降低到-9.00,每头牛每小时可减少热量损失3.31 MJ;由于距离防风墙的远近不同,肉牛日增重相差0.15 kg/(头·d),但差异不显著(P>0.05)。     

固始鹅蛋壳质量性状分析

试验旨在分析固始鹅的蛋壳质量性状,为品种资源普查提供素材。在农户散放饲养的鹅中随机收集56枚鹅蛋,对鹅蛋的蛋壳重占总蛋重的比例和不同部位蛋壳厚度进行测定。结果表明,蛋壳重占总蛋重的比例平均为12.32%;平均蛋壳厚度为0.517 mm,大多数鹅蛋的蛋壳锐端厚度比钝端和中间高。